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Title: Ferromagnetic tunnel contacts to graphene: Contact resistance and spin signal

We report spin transport in CVD graphene-based lateral spin valves using different magnetic contacts. We compared the spin signal amplitude measured on devices where the cobalt layer is directly in contact with the graphene to the one obtained using tunnel contacts. Although a sizeable spin signal (up to ∼2 Ω) is obtained with direct contacts, the signal is strongly enhanced (∼400 Ω) by inserting a tunnel barrier. In addition, we studied the resistance-area product (R.A) of a variety of contacts on CVD graphene. In particular, we compared the R.A products of alumina and magnesium oxide tunnel barriers grown by sputtering deposition of aluminum or magnesium and subsequent natural oxidation under pure oxygen atmosphere or by plasma. When using an alumina tunnel barrier on CVD graphene, the R.A product is high and exhibits a large dispersion. This dispersion can be highly reduced by using a magnesium oxide tunnel barrier, as for the R.A value. This study gives insight in the material quest for reproducible and efficient spin injection in CVD graphene.
Authors:
; ; ; ; ; ; ;  [1] ; ; ; ; ;  [2] ;  [3] ;  [4]
  1. University Grenoble Alpes, CEA, INAC-SP2M, F-38054 Grenoble (France)
  2. Unité Mixte de Physique CNRS-Thales, F-91767 Palaiseau (France)
  3. University Grenoble Alpes, CNRS, CEA, INAC-SPINTEC, Grenoble F-38054 (France)
  4. Crocus Technology, 4 place Robert Schuman, 38000 Grenoble (France)
Publication Date:
OSTI Identifier:
22413160
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM; ALUMINIUM OXIDES; CHEMICAL VAPOR DEPOSITION; COBALT; COMPARATIVE EVALUATIONS; DIFFUSION BARRIERS; ELECTRIC CONDUCTIVITY; GRAPHENE; LAYERS; MAGNESIUM; MAGNESIUM OXIDES; OXIDATION; PLASMA; SPIN; SPUTTERING; VALVES